Studies on factors affecting susceptibility to peer pressure are not plentiful although this susceptibility has been found to be associated with youth problems such as substance use and risky sexual behavior. The present study examined how adolescents’ susceptibility to peer pressure is related to their relationships with mothers and emotional autonomy from parents. Data were collected from 550 Hong Kong secondary school students using questionnaires. Structural equation modeling results showed that mothers’ behavioral control and psychological control predicted adolescents’ susceptibility to peer pressure in negative and positive directions respectively. A mediation model is established in which maternal warmth was a negative predictor of adolescents’ susceptibility to peer pressure in the areas of peer activities, family activities, school activities, and misconduct behaviors and its effects were mediated by adolescents’ emotional autonomy from parents. Implications for parenting programs are discussed.